WO1990003478A1

WO1990003478A1 - Method and apparatus for forming a path for a screeding means

Info

Publication number: WO1990003478A1
Application number: PCT/SE1989/000495
Authority: WO
Inventors: Pell Sune Westhed
Original assignee: Pell Sune Westhed
Priority date: 1988-09-29
Filing date: 1989-09-13
Publication date: 1990-04-05
Also published as: EP0436595A1; FI911545A0

Abstract

The invention relates to a method for forming a screeding path for a vibrating screed or the like being used for the direct smoothing of especially single-course structural floors, whereby support feet (2, 3) being adjustable in heigth are positioned at a distance from each other along the location of a casting joint to be formed and whereby these support feet are intended to support a screeding beam (14). According to the invention each of the support feet are formed by a combination of a base plate (2), a guide tube (3) extended upwardly therefrom, removably attachable thereto and of alternative length, and a slide tube (7) mountable on the guide tube, displaceable along the guide tube and securable thereto, said slide tube (7) having a support (13) for the screeding beam, which support has alternative height. According to the invention guide tubes having different length and slide tubes having screeding beam supports of different height are selected depending upon the thickness of the floor to be cast, whereupon the screeding beam (14) is positioned on the supports (13) of the support feet (2, 3) and is adjusted in height by releasing the locking means of the slide tube (7), by displacing the slide tube along the guide tube and by renewed locking or securing of the slide tube in position. The invention also relates to an apparatus for performing said method.

Description

METHOD AND APPARATUS FOR FORMING A PATH FOR A SCREEDING MEANS.

The present invention relates to a method and an appara- tus for forming a path for a screeding means and speci¬ fically relates to a method and an apparatus for forming a path for a screeding means, such as a vibrating screed or the like being used for the direct smoothing of single-course structural floors, said path being adjust- able in height. The apparatus comprises a foot or base having^"a support for an elongated screeding beam mounted thereon, said support being adjustable in height.

The invention is especially applicable in connection with casting larger single-course structural floors, such as industrial floors which may have an area of up to

5-10000 m . In casti *ng such large areas i *t i *s usually not possible to cast the whole floor at once and for that reason the floor is cast in smaller sections with joints in the floor, between the sections. In the casting of each section it is therefore necessary on the one hand to provide a casting joint support for delimiting the section at the joint position and, on the other hand, to position and level a special screeding beam which forms a path or a guide for a so called vibrating screed or the like which is employed for the screeding and direct smoothing of the concrete.

A great number of different apparatuses intended to solve the above-mentioned problems have previously been dis¬ closed. These previous solutions may be sub-divided into two basic types, namely one that may be dismounted and removed after the casting and another one which is left in position after the casting and which is accordingly cast into the concrete floor, said casting joint supports being either flat or so to say provided with a groove or tenon to bind the joint. Those previously suggested apparatuses intended to be cast into the concrete floor may be in the shape of concrete beams which are set out on the bedding and form the screeding path as well as the casting joint support. However, the disadvantage of such solutions is that the concrete beams are not provided with any possibility for adjustment in height and cannot easily be adapted to floors having different thickness, but must be provided in different dimensions. There is also a danger that such concrete beams being cast into the floor impair the joint by not providing sufficient bearing or carrying strength. As with all other apparatuses intended to be left in the cast floor these concrete beams naturally also suffer from the disadvantage of raised costs, since they can not be re-used.

There are also previously known apparatuses consisting of feet or bases that are set out at a distance from each other along the planned joint and which consist of two portions being connected to each other by means of threads, whereby the feet may be adjusted in height. The upper portion of the feet is provided with a support intended to receive a screeding beam in the shape of a pipe or rod. These previously known feet are only intended to support the screeding beam in the shape of a rod, a pipe or the like, and are intended to be employed together with a separate casting joint support such as an edge board or the like.

When casting and direct smoothing single-course struc¬ tural floors on the ground the conventional procedure has up to now been to lay out piles of concrete spotwise at a distance from each other along the planned joint, where¬ upon adjustable feet have been pushed into the piles of concrete to allow them to stick thereto. The following day when the concrete has cured a screeding beam is posi¬ tioned on these feet. The most serious drawback of this method is that the laying-out of the piles of concrete is expensive both in terms of material and in terms of the time consumed thereby, and that the screeding beam or screeding guide can not be completed on one and the same day, since the adjustable feet have to be cast integral with the piles of concrete and cannot be subject to load until the following day. In addition to this there is the problem that at temperatures below 0°C it is necessary to provide heating in order to make sure that the piles of concrete cure and that the concrete does not freeze.

Accordingly, the object of the present invention is to provide a method and an apparatus of the kind indicated in the introduction, by means of which the above described disadvantages of the known technique may be eliminated to the greatest possible extent and which specifically permit easy adaption to floors having diffe¬ rent thickness. Moreover the apparatus shall be com¬ paratively inexpensive to manufacture.

According to the present invention the above-mentioned objects are achieved by means of a method and an apparatus of the kind claimed in the enclosed patent claims 1 and 4 respectively.

Advantageous embodiments of the invention are claimed in the dependent subclaims.

The invention is more closely described below i-n connec¬ tion with the enclosed drawings, on which:

Fig. 1 in a side view and partially in section illustrates a completed path for a screeding means in accordance with the invention and in a first embodiment for floors without reinforcement,

Fig. 2 is a partial view illustrating the embodiment according to Fig. 1 in a front view, 4

Fig. 3 in a side view and partially in section illustrates a completed path for a screeding means in accordance with the invention and in a second embodiment for floors with reinforcement, 5

Fig. 4 is a partial view illustrating portions of the embodiment of Fig. 3 in a front view,

Fig. 5 is a side view of the foot according to the inven- 10 tion, with an adjustable support means mounted

" thereon,

Fig. 6 illustrates the foot according to the invention as viewed from the left in Fig. 5,

15

Fig. 7 is a top view of the foot of Fig. 5, and

Fig. 8 is a partial view of a screeding beam for use in connection with casting floors with reinforcement.

20

It should be pointed out that although the method and apparatus according to the invention is primarily inten¬ ded to be used in connection with casting single-course structural floors or base slabs on the ground, it is 25 under certain circumstances also possible to employ them in connection with casting floors.

As illustrated especially in Figs. 5-7 the apparatus according to the invention comprises a base or foot 1

30 consisting of a base plate 2 intended to support the apparatus on the ground and, in the illustrated embodi¬ ment, having a rectangular shape and being manufactured from for instance flat bar steel. However, the shape of the base plate may be varied and it should only have

35 sufficient dimensions to provide a stable support for the screeding beam on the ground. In a preferred embodiment the base plate may be 100 mm wide, 180 mm long and 5 mm thick. A guide tube 3 is removably attached to the upper side of the base plate 2, substantially in a central position thereon. In the illustrated embodiment the removable attachment is achieved by welding a nut 4 to the lower end of the tube 3, whereupon the nut may be screwed onto a threaded pin 5 (only indicated in Fig. 5) extending up through the upper surface of the base plate 2 and being firmly connected thereto. In order to permit a firm tightening of the guide tube 3 against the base plate 2, and reverse a loosening of the guide tube, a through bore 6 may be provided adjacent the upper end of the guide tube, so that for instance a screw driver may be pushed in through the bore to facilitate the turning or rotation of the guide tube. The nut 4 may alter¬ natively be provided inside the lower end of the guide tube.

Although this guide tube in the illustrated embodiment has a cylindrical shape, it should be pointed out that the invention is not restricted to this configuration, but that the guide tube may for instance also have a square cross-section, whereby it is only of importance that those portions of the below described slide tube 7 which co-operatate with the guide tube have a corresponding shape. The guide tube 3 is manufactured in different lengths of for instance between 70 and 300 mm and through the above described removable attachment of the guide tube to the base plate the guide tube may be easily replaced for adaption to different thickness of the floors to be cast.

On the guide tube 3 is mounted a slide tube 7 which for permitting an adjustment of the height of the screeding path is manufactured having a cross-sectional shape substantially corresponding to that of the guide tube 3, but having a slightly larger inner dimension than the outer dimension of the guide tube, so that it may be dis¬ placed along the guide tube 3. For locking or securing the slide tube 7 in the desired position it is provided with a locking device consisting of a locking washer or securing plate 8 having an aperture 9 the inner dimen¬ sions of which corresponds to the inner dimensions of the slide tube 7, i.e. such that the securing plate 8 in a substantially horizontal position may be displaced freely along the guide tube 3, but such that it engages and is secured to the guide tube when it is tilted to a position inclined in relation to the horizontal.

At one of its sides the securing plate 8 is pivotally connected to the slide tube 7 and in the illustrated embodiment this pivotal connection has been achieved by providing the securing plate with two lugs 10 inserted through the corresponding apertures 11 in a support 13 firmly attached to the slide tube 7 and intended to support the actual screeding beam 14. The lugs are slightly bent upwardly at their free ends in o'rder not to slip out of the apertures 11. At the side of the securing plate 8 opposite that of the lugs 10, the securing plate is connected to the slide tube 7 through a spring 12. Thus, the spring 12 will normally pull the securing plate 8 to an inclined position for securing the plate and the slide tube 7 in position on the guide tube 3. In adjus¬ ting the position of the slide tube 7 the securing plate 8 is pressed down with a finger to a substantially hori¬ zontal position such that the plate and the slide tube may be freely displaced along the guide tube. With this securing structure the slide tube 7 is safely secured in the desired position, and it is also clear that the more the slide tube is loaded the more firmly the securing plate engages the guide tube 3, and thereby a very stable support for the screeding beam and the vibrating screed is achieved.

As mentioned above a support 13 is welded to the slide tube 7 for supporting the actual screeding beam 14 on an upper, angled portion of the support. Apart from the fact that guide tubes 3 of different length may be mounted to the base plate, these different guide tubes may also be combined with different configu¬ rations of slide tubes 7 with the upper angled portion of the support 13, extending upwardly past the actual slide tube, having different height. This makes it possible to obtain optimum adaption of the supporting base 1 to the thickness of the floor to be cast. Preferably different slide tubes are manufactured, with the support 13 pro- truding for instance 15 mm, 35 mm and 85 mm upwardly past the upper portion of the actual slide tube.

The screeding beam is in itself provided in two different variants 14, 14' intended for casting floors with re- inforcement and without reinforcement respectively. The screeding beam for casting floors without reinforcement is provided with an upper hook-like portion 15 having a first or outer vertical portion 15a intended to grip behind the support 13 in its mounted condition; a second, horizontal position 15b intended to rest on the angled portion of the support 13 and forming the actual scree¬ ding path; and a third vertical portion 15c extending down past the outer end of the angled portion of the support 13, whereby the screeding beam 14 is securely maintained in position on the support. Moreover, the screeding beam 14 is provided with a substantially verti¬ cal portion 16 connected to the third, vertical portion 15c and forming a casting joint support against which a section of the concrete floor is cast. This lower portion 16 of the screeding beam 14 is preferably provided with a longitudinal groove 16a. When casting a section this groove 16a formes a recess (tenon) for the next section to be cast against the first section; this provides a better joint between the sections and also stiffens the actual screeding beam which is preferably manufactured in lengths of 4 meter. Finally the lower portion 16 of the screeding beam 14 is also provided with a horizontally angled portion 16b intended to be positioned close to the ground, forming the lower portion of the casting joint support and with its outer end abutting the guide tube for further stabilization of the s creeding beam. As illustrated in Figs. 1 and 2 the screeding beam may also be provided with knock-out punchings 16c in the region of the longitudinal groove 16a. In these punchings there may be provided mortise bolts 16d which are cast into the concrete for further stabilization of the joint.

This screeding beam for casting without reinforcement is manufactured in different configurations with different heights h , for instance in configurations with h = 110 mm and h = 140 mm, and this means that by chosing a suitable guide tube, slide tube and screeding beam it is possible to cover floor-thicknesses from 70-310 mm.

The screeding beam 14' for use in casting concrete floors with reinforcement, is provided with the same hook-like upper portion 15' as described above, but i s provided with a straight and shorter lower portion 16' intended to cooperate with a casting joint support of a conventional type , which wil l be described more closely below. The screeding beam 14' for concrete floors with reinforcement is furthermore, at the lower portion 16 ' thereof , pro- vided with a number of slots 17 extending from the lower, longitudinal edge thereof and a distance up towards the upper portion of the s creeding beam (Fig. 8 ) . The s lots 17 are provided along the lower edge at a distance of approximately 100 mm from each other, and are intended to receive reinforcement bars of the top reinforcement of the floor.

The method a ccording to the invention w i l l now b e described with specific reference to Figs. 1-4. Initially support feet or bases 11 adapted to the thickness of the concrete f loor to be cast are put in order, i. e. base p lates 2 are provided with guide tubes 3 of suitable length. Slide tubes 7 which are likewise adapted to the thickness of the floor to be cast, are subsequently moun¬ ted on the guide tubes 3 of the support bases 1. Then, the bases 1 are aligned with each other, with a mutual spacing of for instance 1-2 meter, along the position of the casting joint of the section of the concrete floor to be cast.

In order to prevent the support bases from sliding back— wardly due to the pressure from the concrete, a steel tip 18 is preferably driven down behind the respective base plate^" 2. Alternatively the base plate 2 may also be provided with a bore (not shown) in the region of its rear end, through which bore the steel tip is driven down.

When the support bases 1 are assembled and completed and are positioned and fixed in the described manner the screeding beam 14, likewise selected according to the thickness of the concrete floor, may be hooked to the supports of the slide tubes 7 with the upper hook-like portion 15 abutting and partly gripping the upper portion of the support 13. The screeding beam 14 is finally adjusted to the correct height by releasing the locking of the slide tube 7 to the guide tube 3, which is achieved by pressing down the securing plate 8 at its end closest to the spring 12, whereby the slide tube 7 may be freely pushed upwardly or downwardly along the guide tube for the adjustment. As soon as the securing plate is un¬ loaded it engages the guide tube 3 again and thereby secures the slide tube 7 and the screeding beam 14 in the desired position.

When the section has been cast and has been screeded by means of a vibrating screed or the like, the support bases 1 are removed by actuating the securing plate 8 again, such that the slide tube 7 may be brought down¬ wardly along the guide tube 3 until it is free from the screeding beam 14 and such that the complete base 1 may be removed. Finally the screeding beam 14 is also removed from the cast concrete section, whereupon the procedure may be repeated for casting a new section.

In casting concrete floors with reinforcement a casting joint support 18 of a conventional type is initially pro¬ vided on the bottom reinforcement 19 and is tied thereto. Such a casting joint support normally consists of a flat, elongated plate which may be provided with a longitudinal groove, corresponding to the groove 16a of the screeding beam 14, for forming a recess. Angled bars are preferably provided at the rear side of the elongated plate and at a mutual distance of for instance 80 mm along the plate, whereby one leg of the angled bar is connected to the plate and the other leg is extended perpendicularly, rearwardly from the plate. Possibly a concrete block 20 is also provided under the bottom reinforcement for sealing off the section so that concrete is prevented from leaking out under the reinforcement.

The support bases 1 are then assembled and completed in the manner described above and are positioned along the position of the casting joint, whereby the mutual dis¬ tance between the support bases may vary somewhat depen- ding upon how the reinforcement is laid. The support bases 1 are set out at a distance just behind the casting joint support 18 and then the screeding beam is hooked on, and in this case the straight screeding beam 14' is selected, which is provided with slots 17 opening at the lower edge of the beam. The top reinforcement 21 is inserted into the s lots 17 and due to the fact that the support bases 1 have been positioned in correct position behind the casting joint support 18 the lower end of the screeding beam 14' will overlap and closely join the upper end of the casting joint support 18 for forming an adequate casting joint support in cooperation therewith . In this case the adaption of the screeding beam to the thickness of the floor to be cast is, as in the above described case, carried out by chosing the appropriate guide tube 8 and slide tube 7. However, the screeding beam 14' is preferably manufactured in only one width so that the adaption of the casting joint support to floors having different thickness will be carried out by selec¬ ting casting joint supports 18 of different height or width or by cutting off the casting joint supports to the correct height or width.

The adjustment of the screeding beam to the correct height as well as the removal of the support bases and of the screeding beam is carried out in a manner correspon- ding to that described above.

In the light of the above description it is now obvious that by using the method and the apparatus according to the invention essential advantages are achieved in rela- tion to the previously known technique. The most essen¬ tial advantages are: that the simple adaption of the screeding beam to the varying thickness of the floor to be cast is achieved; that a simple adjustment of the screeding beam to the correct height is achieved; that a safe and reliable locking of the screeding beam in the set position is achieved; that the floor may be cast and screeded on the same day as the screeding path is formed; that the screeding path may be formed regardless of if the temperature is below 0°C; and that a possibility for easy adaption to casting with or without reinforcement is achieved.

Although preferred embodiments of the invention have been described above it should be obvious that the invention is not restricted to said embodiments but also encompasses modifications and alterations thereof which are obvious to a man skilled in the art. Accordingly, the scope of the invention should only be restricted by the enclosed patent claims.

Claims

1. A method of forming a screeding path for a vibrating screed or the like, especially in casting single-course structural floors, whereby support feet adjustable in height are positioned at a distance from each other along the location of a casting joint to be formed and whereby these support feet are intended for supporting a screeding beam, characterized in that each of the support feet is formed by a combination of a base plate, a guide tube having alternative length, being extended upwardly from the base plate and being removably connect- able to the base plate, and a slide tube having a support for the screeding beam and being mountable to, displace- able along and securable to the guide tube, said support having alternative height, and in that guide tubes having different lengths and slide tubes having screeding beam supports of different height are selected depending upon the thickness of the floor to be cast, whereupon the screeding beam is positioned on the supports of the support feet and are adjusted in height by releasing the locking of the slide tube, by displacing the slide tube along the guide tube and by renewed locking or securing of the slide tube in position.

2. A method according to claim 1 for use in connection with casting floors without reinforcement, characterized in that the screeding beam is formed having-an upper horizontal portion forming the actual screeding path and a substantially vertical portion connected to the hori¬ zontal portion and forming a casting joint support, whereby, depending upon the thickness of the floor to be cast, the screeding beam is selected having a vertical portion of such a height that it extends substantially down to the bedding on which the floor is cast.

3. A method according to claim 1 for use in connection with casting floors with reinforcement, characterized in that a screeding beam is selected comprising an upper horizontal portion forming the actual screeding path, a lower, substantially vertical portion forming an upper portion of a casting joint support and a number of slots provided at uniform distances from each other along the length of the screeding beam and opening at the lower edge of the vertical portion for receiving the top re¬ inforcement of the floor, in that for forming the complete casting joint support the screeding beam is combined with a casting joint support of conventional type, -which is attached to the bottom reinforcement of the floor and whiσh is brought to coincide with and to cooperate with the vertical portion of the screeding beam for forming the lower portion of the casting joint support.

4. Apparatus for forming a screeding path for a vibra¬ ting screed or the like, especially in connection with casting single-course structural floors, and consisting of support feet being adjustable in height and being intended for supporting a screeding beam (14, 14'), characterized in that the support foot (1) consists of a base plate (2) intended to be positioned on the bedding, a guide tube (3) removably mounted on the base plate and extended upwardly from the base plate, a slide tube (7) being removably mounted to the guide tube, being dis- placeable along the guide tube and being securable in a desired position thereto, said slide tube (7) comprising a support (13) for supporting the screeding beam (14, 14') which comprises an upper hook-like portion (15, 15') intended to grip the support (13) and a lower vertical portion (16, 16') intended to form at least a portion of a casting joint support.

5. Apparatus according to claim 4, characterized in that the replaceable guide tube (3) is manufactured having alternative lengths between for instance 70 and 300 mm and in that the likewise replaceable slide tube (7) comprises a support (13) having an alternative height above the actual slide tube of for instance 15 mm, 35 mm and 85 mm.

6. Apparatus according to claim 4 or 5, characterized in that the slide tube comprises a locking means consis¬ ting of a securing plate (8) which at one of its sides is pivotally connected to the slide tube (7) or alternative¬ ly to the support (13), and at its opposite side is con- nected to the slide tube (7) through a spring (12) and which" is provided with an aperture (9) for receiving the guide tube (3), whereby the aperture (9) has such dimen¬ sions in relation to the outer dimension of the guide tube (3) that the securing plate (8) in a substantially horizontal position is freely displaceable along the guide tube, but in a position inclined in relation to the horizontal engages the guide tube and secures the slide tube thereto.

7. Apparatus according to any of claims 4-6 for use in connection with casting floors without reinforcement, characterized in that the substantially vertical portion (16) of the screeding beam (14) is of such height or width that it substantially corresponds to the thickness of the floor to be cast.

8. Apparatus according to claim 7, characterized in that the substantially vertical portion (16) of the screeding beam (14) at its lower end comprises a horizon- tally angled portion (16b) which in the mounted condition is intended to abut the guide tube (3).

9. Apparatus according to any of claims 4-6 for use in connection with casting floors with reinforcement, characterized in that the lower, substantially vertical portion (16') of the screeding beam (14) is of a height or width extending only over a portion of the thickness of the floor to be cast and in that the vertical portion (16') is provided with slots (17) provided at a distance from each other along the length of the screeding beam (14'), opening at the lower edge of the vertical portion (16') and extending upwardly therefrom.

10. Apparatus according to any of claims 4-9, charac¬ terized in that the upper, hook-shaped portion (15, 15') of the screeding beam (14, 14') consists of a first or outer vertical portion (15a) intended to grip behind the support (13) in the mounted condition, a second horizon¬ tal portion (15b) intended to rest on an angled portion of the support (13) and forming the actual screeding path, and a third, vertical portion (15c) extending down past the outer end of the angled portion of the support (13).